Outbreak Of Anthracnose Research Articles

Overexpression of dihydroflavonol 4-reductase (CoDFR) boosts flavonoid production involved in the anthracnose resistance.

The outbreak of anthracnose caused by Colletotrichum spp. represents a devastating epidemic that severely affects oil tea (Camellia oleifera) production in China. However, the unknown resistance mechanism to anthracnose in C. oleifera has impeded the progress of breeding disease-resistant varieties. In this study, we investigated the physiological responses of resistant and susceptible lines during C. gloeosporioides infection. Our results showed that the accumulation of malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) in both disease-resistant and susceptible lines increased by C. gloeosporioides infection. Also, disease-resistant lines exhibited lower MDA, but higher POD, SOD, and CAT activities compared to susceptible lines. The accumulation of flavonoids in both resistant and susceptible C. oleifera leaves increased following C. gloeosporioides infection, and the increase was greater in resistant lines. Further, we identified and functionally characterized the dihydroflavonol 4-reductase (CoDFR) from the resistant C. oleifera line. We showed that the full-length coding sequence (CDS) of CoDFR is 1044 bp encoding 347 amino acids. The overexpression of CoDFR in tobacco altered the expression of flavonoid biosynthetic genes, resulting in an increased flavonoid content in leaves. CoDFR transgenic tobacco plants exhibited increased anthracnose resistance. Furthermore, the transgenic plants had higher salicylic acid content. These findings offer potential insights into the pivotal role of CoDFR involved in flavonoid-mediated defense mechanisms during anthracnose invasion in resistant C. oleifera.

Colletotrichum gloeosporioides s.l. causes an outbreak of anthracnose of cacao in Ghana

Outbreak of anthracnose of cacao (Theobroma cacao L.), covering an estimated total growing area of 248.47 hectares, occurred in parts of Ghana from July to October 2019. Disease samples were collected from the outbreak areas to isolate and identify the pathogen and establish its pathogenicity. Disease symptoms appeared on leaves as dark brown patches with yellow halo margins. Colletotrichum gloeosporioides s.l. was isolated from infected plant tissues and pathogenicity tests confirmed it as the causative agent. The disease was widespread in the Prestea-Huni Valley district of the Western Region, particularly in the Yareyeya community, where a 14.8-hectare farm was seriously affected. Anthracnose has long been known as a sporadic but minor disease of cacao in Ghana. The current shift in status and rapid spread of the disease from infected farms to new farms, though it may or may not be contiguous, cannot be readily explained. Application of copper fungicides, namely Nordox 75 WG (86% cuprous oxide), Champion (77% cupric hydroxide) and Royal Cop 50 WP (77% copper hydroxide) at 75 g, 100 g and 100 g, respectively, each in 15 litres of water, at 2-week intervals for four months, effectively managed the disease.

Colletotrichum species causing anthracnose on avocado fruit in Mexico: Current status

AbstractColletotrichum species cause anthracnose disease in tropical and subtropical fruit crops worldwide. Mexico is the main producer and exporter of avocado (Persea americana) globally and has yearly outbreaks of anthracnose on this crop. However, which specific Colletotrichum spp. cause these outbreaks in avocado‐producing regions remain uncertain; thus, the objective of the present study was to identify the species responsible. A survey performed in six production regions of Mexico yielded 232 isolates, from which a subset of 104 strains was selected based on morphological characteristics and origin. This subset was sequenced and haplotypes were analysed in the gapdh partial gene. Finally, 31 strains were identified through multilocus phylogenetic analyses using the sequences of the internal transcribed spacer region and six loci. This study revealed the presence of two species previously reported in Mexico (C. karsti and C. godetiae), three novel records in Mexico (C. siamense, C. fioriniae, and C. cigarro), four novel records on avocado (C. chrysophilum, C. jiangxiense, C. tropicale, and C. nymphaeae), and two novel lineages (Colletotrichum sp. 1 and Colletotrichum sp. 2). C. siamense was the most prevalent, while the species reported for the first time on avocado, including the novel lineages, were the least prevalent. C. karsti was the most widespread (four regions), followed by C. siamense, C. jiangxiense, and C. chrysophilum (three regions). Pathogenicity tests showed that all species caused anthracnose on avocado fruit. These findings will be useful for improving the management of avocado anthracnose outbreaks in Mexico.

Amorphophallus konjac anthracnose caused by Colletotrichum siamense in China.

Amorphophallus konjac is an important commercial crop grown in China because it is the only plant species which is rich in glucomannan concentration. Recently, an outbreak of anthracnose (incidence ranging from 10-15%) was observed in a field survey conducted from June to August 2018. This study aims to identify the causal agent of A. konjac anthracnose. The pathogen was isolated on potato dextrose agar (PDA) medium. The fungal colony on PDA was greyish to dark grey. Conidia were falcate, one-celled and hyaline. Based on the micro-morphological and cultural characteristics, the pathogen was identified as Colletotrichum sp. blast search and phylogenetic analysis of the ITS, GAPDH, CHS1, ACT, CAL and TUB2 genes revealed the pathogen as Colletotrichum siamense. Koch's postulates were conducted on 2-month konjac leaves with conidial suspension. Development of typical anthracnose disease was recorded 5days after inoculation and the pathogen's identity was confirmed by re-isolation and molecular identification. Amorphophallus konjac anthracnose was caused by C. siamense in China. Identification of causal agent of A. konjac anthracnose will be helpful in designing effective disease control strategies.

Outbreak of anthracnose on apricots caused by Colletotrichum fioriniae in Slovenia

In 2012 and 2013 apricots ( Prunus armeniaca ) showing circular, brown and slightly sunken necrotic lesions on the fruit surface were observed in commercial orchards near Nova Gorica (western Slovenia). When placed in humid conditions…

Outbreak of Anthracnose on Hibiscus cannabinus Caused by Colletotrichum sp. in Korea

Outbreak of Anthracnose on <i>Hibiscus cannabinus</i> Caused by <i>Colletotrichum</i> sp. in Korea

Colletotrichum siamense and C. truncatum are responsible for severe outbreaks of anthracnose on onion in southwest India.

Colletotrichum species responsible for severe outbreaks of anthracnose on onion in southwest India are reported. These fungi produced white, oval sunken lesions on the leaves and neck at the onset of infection followed by appearance of necrotic centres with grey-colored concentric rings of acervuli, which eventually covered the whole leaves and subsequently led to collapse of the plant. Thirty seven isolates of Colletotrichum recovered from diseased leaves and neck were characterized based on morphological characteristics and partial sequences of ACT, TUB2, CHS-1, CAL, CYLH3, GAPDH, GS and ITS genes. The combined multilocus sequence analysis coupled with a critical examination of the phenotypic characters revealed the presence of two species, Colletotrichum siamense (27 isolates) and Colletotrichum truncatum (10 isolates). Pathogenicity of both species was ascertained on onion seedlings of cv. Arka kalyan. To our knowledge, this is the first report of C. siamense and C. truncatum causing anthracnose disease on onion.

First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Soybean (Glycine max) in Malaysia.

Soybean (Glycine max L.) is one of the most economically important crops in the world, and anthracnose is known to infect soybean in most countries. Colletotrichum truncatum is the common pathogen causing anthracnose of soybean. However, at least five species of Colletotrichum have been reported on soybean worldwide (2). In July 2010, anthracnose symptoms were observed on soybean in the experimental fields of the agriculture station in Ladang Dua, University Putra Malaysia located in Selangor state of Malaysia. Symptoms were initially observed on a few plants randomly within one field, but after 4 weeks, the disease was found in two additional fields scattered across an area of 1 km2. Pinkish-brown lesions were observed on the pods, and the formation of dark lesions on the leaves and stems was sometimes followed by stem girdling, dieback, and distorted growth. At later stages, numerous epidermal acervuli developed in the lesions, and mucilaginous conidial masses appeared during periods of high relative humidity. Conidia produced in acervuli were straight, cylindric, hyaline, and aseptate, with both ends rounded. Conidia measured (mean ± SD) 14.2 ± 0.6 × 3.6 ± 0.7 μm, and the L/W ratio was 3.95 μm. Six isolates of the fungus were obtained and identified as C. gloeosporioides on the basis of morphological characterization (3). The isolates were deposited in the University Putra of Malaysia Culture Collection (UPMCC). PDA cultures were white at first and subsequently became grayish to pink to reddish-brown. Amplification and sequence analysis of coding and none-coding regions of the ITS-rDNA (GenBank JX669450), actin (JX827430), β-tubulin (JX827454), histone (JX827448), chitin synthase (JX827436), and glyceraldehyde-3-phosphate dehydrogenase (JX827442) obtained from the representative isolate, CGM50, aligned with deposited sequences from GenBank and revealed 99 to 100% sequence identity with C. gloeosporioides strains (JX258757, JX009790, GQ849434, HM575301, JQ005413, and JX00948 from GenBank). One representative isolate, CGM50, was used for pathogenicity testing. Four non-infected detached leaves and pods of 24-day-old G. max var. Palmetto were surface-sterilized and inoculated by placing 10 μl of a conidial suspension (106 conidia ml-1) using either the wound/drop or non-wound/drop method (4), with 10 μl distilled water as a negative control. Leaves and pods were incubated at 25°C, 98% RH. The experiment was repeated twice. Five days after inoculation, the development of typical field symptoms, including acervuli formation, occurred on the leaves and pods of inoculated plants, but not on the negative controls. A fungus with the same colony and conidial morphology as CGM50 was recovered from the lesions on the inoculated leaves and pods. Anthracnose caused by C. gloeosporioides on soybean plants has been reported previously in different countries, but not in Malaysia (3). Geographically, the climate of Malaysia is highly conducive to maintain and cause outbreaks of anthracnose all year round; thus, the development of management recommendations will be inevitable for anthracnose control. To our knowledge, this is the first report of C. gloeosporioides causing anthracnose on soybean in Malaysia.

Heterologous overexpression of Glomerella cingulata FAD-dependent glucose dehydrogenase in Escherichia coli and Pichia pastoris

BackgroundFAD dependent glucose dehydrogenase (GDH) currently raises enormous interest in the field of glucose biosensors. Due to its superior properties such as high turnover rate, substrate specificity and oxygen independence, GDH makes its way into glucose biosensing. The recently discovered GDH from the ascomycete Glomerella cingulata is a novel candidate for such an electrochemical application, but also of interest to study the plant-pathogen interaction of a family of wide-spread, crop destroying fungi. Heterologous expression is a necessity to facilitate the production of GDH for biotechnological applications and to study its physiological role in the outbreak of anthracnose caused by Glomerella (anamorph Colletotrichum) spp.ResultsHeterologous expression of active G. cingulata GDH has been achieved in both Escherichia coli and Pichia pastoris, however, the expressed volumetric activity was about 4800-fold higher in P. pastoris. Expression in E. coli resulted mainly in the formation of inclusion bodies and only after co-expression with molecular chaperones enzymatic activity was detected. The fed-batch cultivation of a P. pastoris transformant resulted in an expression of 48,000 U L-1 of GDH activity (57 mg L-1). Recombinant GDH was purified by a two-step purification procedure with a yield of 71%. Comparative characterization of molecular and catalytic properties shows identical features for the GDH expressed in P. pastoris and the wild-type enzyme from its natural fungal source.ConclusionsThe heterologous expression of active GDH was greatly favoured in the eukaryotic host. The efficient expression in P. pastoris facilitates the production of genetically engineered GDH variants for electrochemical-, physiological- and structural studies.

Colletotrichum gloeosporioides Penzig (Penzig) &amp; Saccardoによるヤエヤマアオキ炭疽病（新称）

An outbreak of anthracnose on Indian mulberry (Morinda citrifolia L.) was recorded in Okinawa Prefecture in 2006. Abundant conidial masses formed on the surface of brown spots or zonate brown spots on leaves. A Colletotrichum species was isolated from the diseased leaves and stems, and typical symptoms were reproduced after inoculation of either wounded or intact leaves. The causal agent was identified as Colletotrichum gloeosporioides based on morphological characters and growth temperature.

Fungicide seed treatments reduce seed transmission and severity of lupin anthracnose caused by Colletotrichum gloeosporioides

Lupin production is a vital part of the farming system on coarse-textured soils throughout Western Australia. The continued viability of the lupin industry was threatened in 1996 by the outbreak of anthracnose caused by Colletotrichum gloeosporioides. The use of fungicides as seed dressings was investigated as a potential control for this disease. Twenty one fungicides were examined in vitro for their effect on growth of C. gloeosporioides: nine fungicides, including thiram and fluquinconazole, were identified with ED50 of less than 1.0 μg/mL. In a series of glasshouse experiments using artificial spray inoculation, and field experiments using rain-splashed infection from infected spreader plots, seed treatment with carbendazim or fluquinconazole provided lupin seedlings with systemic protection from anthracnose infection. Iprodione, procymidone and thiram showed no systemic activity against anthracnose. In field experiments, thiram, fluquinconazole and carbendazim were able to reduce anthracnose transmission from infected seed. Iprodione and procymidone, widely used on lupin seed in Western Australia for control of brown spot caused by Pleiochaeta setosa, did not provide systemic protection from anthracnose and were not as effective as other fungicides at reducing seed transmission. The efficacy of thiram, fluquinconazole or carbendazim was not reduced by mixing with iprodione or procymidone and these mixtures were generally more effective than iprodione or procymidone alone. As a result of these investigations, thiram has been registered as a seed treatment in Western Australia for control of anthracnose seed transmission in lupins.

Vegetative compatibility amongst isolates of Colletotrichum causing lupin anthracnose

Isolates of Colletotrichum pathogenic on Lupinus spp, were characterised by vegetative compatibility analysis with two vegetative compatibility groups (VCGs) being identified. Isolates of Colletotrichum from North America and France belonged to VCG-1 whereas isolates of Colletotrichum collected in Western Australia during an outbreak of anthracnose on lupin seed imported from Germany in 1994 belonged to VCG-2. VCG-2 was also shown to occur in Chile where it possibly fust originated. Complementation tests with putative isolates of Colletotrichum gloeosporioides from other hosts provided no evidence that either VCG-1 or VCG-2 otherwise occurs in Australia. L. angustifolius cv. Illyarrie, reputedly resistant to anthracnose, was not resistant to VCG-2 in glasshouse tests.

Investigations into Sources of Resistance to Tobacco Anthracnose, Colletotrichum tabacum (Boning), in Malawi

Abstract Tobacco in Malawi often suffers from outbreaks of anthracnose caused by Colletotrichum tabacum (Boning); particularly at the seedling stage. In order to identify suitable sources of resistance for use in a breeding programme three varieties of Nicotiana tabacum and eight other Nicotiana species were tested in the greenhouse trials, three varieties of N. tabacum and five other Nicotiana species were tested in seedbed trials. The most promising sources appeared to be N. sanderae or N. debneyi, and possibly N. nudicaulis or N. forgetiana.